Basic eukaryotic cell biology (1)

Introduction to Eukaryotic Cell Biology

  • Basic Eukaryotic Cell Biology by Dr. Jason Gill

  • Newcastle University overview of organs, tissues, and cells

Cell Size and Structure

  • Eukaryotic cells range from 1mm to 1µm.

  • Importance of large surface area for material exchange (surface-area-to-volume ratio).

    • Large cells have decreased surface area relative to volume.

    • Specialized cells like those in absorption have structures (e.g., microvilli) to increase their surface area.

Prokaryotic Cells

  • Two domains:

    • Bacteria

    • Archaea

  • Characteristics:

    • Smaller and simpler than eukaryotic cells.

    • Lacks membrane-bound nucleus.

    • Shapes: spherical (coccus), rod (bacillus), spiral (spirillum/spirochete).

Prokaryotic Cell Structures

  • Key Components:

    • Inclusion body: Nutrient storage.

    • Mesosome: Plasma membrane folds to increase surface area.

    • Ribosome: Protein synthesis site.

    • Nucleoid: Bacterial chromosome location.

    • Glycocalyx: Gel coating outside the cell wall.

    • Conjugation pilus: DNA transfer apparatus.

    • Fimbriae: Adhesion aids.

    • Flagellum: Motility.

Eukaryotic Cells

  • Domain: Eukarya includes protists, fungi, plants, and animals.

  • Characteristics:

    • Contains membrane-bound nucleus and specialized organelles.

    • Generally larger than prokaryotic cells.

Hypothesized Origin of Eukaryotic Cells

  1. Nucleus formation via membrane invagination.

  2. Endomembrane system development.

  3. Acquisition of mitochondria from aerobic bacteria.

Components of Animal Cells

  • Nucleus: Genetic material storage.

  • Mitochondrion: ATP production site.

  • Endoplasmic Reticulum (ER):

    • Rough ER:** Protein synthesis and modification.

    • Smooth ER: Lipid synthesis.

  • Golgi Apparatus: Protein processing and packaging.

  • Lysosome: Intracellular digestion.

Eukaryotic Cell Functionality

  • Function of Ribosomes: mRNA translation to polypeptides.

  • Summary of cellular organelles:

    • Nucleus, mitochondria, Golgi apparatus, lysosomes, etc.

Cell Membrane and Cytoskeleton

  • Cell Membrane: Phospholipid bilayer with proteins.

  • Cytoskeleton: Structural support and movement aid.

    • Includes actin filaments, intermediate filaments, microtubules.

Comparison of Prokaryotic and Eukaryotic Cells

  • Eukaryotic (10-100 µm) vs. Prokaryotic (1-20 µm):

    • Cell Wall: Peptidoglycan (Prokaryotic) vs. absent (Eukaryotic).

    • Nucleus: Present in Eukaryotic, absent in Prokaryotic.

    • Organelles: Various in Eukaryotic, limited in Prokaryotic.

Conclusion

  • Eukaryotic cells are complex and functional diverse, with specialized structures facilitating various cellular processes.